US3826367A

US3826367A - Grain cleaner

Info

Publication number: US3826367A
Application number: US00228684A
Authority: US
Inventors: L Hubach
Original assignee: WS Tyler Inc
Current assignee: WS Tyler Inc
Priority date: 1969-01-30
Filing date: 1972-02-23
Publication date: 1974-07-30
Anticipated expiration: 1991-07-30

Abstract

A grain cleaner including, in series, an inlet manifold, vibrating apparatus, an outlet manifold and vertically extending chutes. The inlet manifold includes an opening at the top for receiving a mixture of grain and foreign matter and side walls converging downwardly toward outlets, said manifold being constructed to allow linear flow of said grain from said opening to said outlets. The outlets being located at one side of the inlet manifold near the lower end, each one being constructed to feed a stream of the substantially dry mixture to one of a plurality of superposed screening decks. The mixture flowing through the outlets may be individually regulated by pivotable gates disposed therein to give uniform flows to each deck. Each deck includes a screen superposed over a pan. Whole grains are retained above the screen and fines consisting of foreign matter, broken grains, and undersized grains fall through the pores of the screen onto the pan. A vibrator is operatively assembled to shake the box and its contents at an acceleration of at least three times that of gravity and to exert a throw on the fines which is adequate to cause them to strike the underside of the screen and dislodge any material blinding any of the openings. The outlet manifold includes two outlets from each deck. One outlet is disposed to receive the grain which is retained on the screen. The other outlet is disposed to receive the fines on the pan. A passage in the outlet manifold adjoins each of the outlets and baffles are provided therein to horizontally deflect the grain or fines into different vertically extending chutes. Below the outlet manifold, the chutes are structured to laterally deflect the grain in one direction and the fines in another direction whereby all the grain will empty into a single duct and the fines will empty into another single duct.

Description

United States Patent 1191 ubach *July 30, 1974 GRAIN CLEANER [57] ABSTRACT [7 Inventor! LOlliS Hllbach, a, Ohio A grain cleaner including, in series, an inlet manifold, vibrating apparatus, an outlet manifold and vertically [73] Asslgnee Tyler lnyorporated extending chutes. The inlet manifold includes an Cleveland Ohm opening at the top for receiving a mixture of grain and Notice: The portion of the term of this foreign matter and side walls converging downwardly patent subsequent to Aug. 1, I989, toward outlets, said manifold being constructed to has been disclaimed. allow linear flow of said grain from said opening to said outlets. The outlets being located at one side of [22] Fllw' 1972 the inlet manifold near the lower end, each one being [21] Appl. No.: 228,684 constructed to feed a stream of the substantlally dry mixture to one of a plurality of superposed screening Apphcatmn Data decks. The mixture flowing through the outlets may be [63] gg g fi g gt 22 795260 individually regulated by 'pivotable gates disposed therein to give uniform flows to each deck. Each deck includes a screen superposed over a pan. Whole grains [52] Cl 209/243 209/254 0 2 are retained above the screen and fines consisting of [51] Int Cl B07b 1/46 foreign matter, broken grains, and undersized grains o 0 l l e l e u a I i l s l s l e e l u u u a s 0 u Io A [58] Field of Search 209/347, 254,498, 240, t l bl dt h k th b d 209/3154 243 222/564 137/608 v1 ra or is opera weyassem e os a e e ox an 1ts contents at an acceleration of at least three t1mes 56 R f d that of gravity and to exert a throw on the fines which 1 e erences N is adequate to cause them to strike the underside of UNITED STATES PATENTS the screen and dislodge any material blinding any of 440,301 1 1/1890 Buurman 209/347 the openings. The outlet manifold includes two outlets 695,654 3/1902 Sh m 209/493 X from each deck. One outlet is disposed to receive the l i 58 52 grain which is retained on the screen. The other outlet is disposed to receive the fines on the pan. A passage 2,191,0l9 2/l940 Johnson 137/608 X in the Outlet manifold adjoins each of the Outlets and 1271.480 l/l942 G1bson [37/608 X b ffl I d h h H d fl h 2,361,927 11 1944 Buckman 209/498 es prov f t '1 y e i 6 2.952362 9/1960 Johnston 209/498 x gram or fines different, vertlcany extendmg 5.425.552 2/1969 Curtis 209/317 x chutes Below the Outlet ma ifo d. he chutes e 311301597 8/1972 Hubach 209/240 structured to laterally deflect the grain in one direc- 31188902 9/1972 Hubach 209/240 tion and the fines in another direction whereby all the Primary Examiner-Robert Halper Attorney, Agent, or Firn1Fay & Sharpe grain will empty into a single duct and the fines will empty into another single duct.

54 OUTLET PAIENImJuLwmm SHEET 10F 4 FROM gsCALPER FIG. I

INLET MANIFOLD 24 IHIII ACCEPTABLE GRAIN FINES PATENIEnJmsmsm 3.828.361

Sum 2 or 4 GRAIN h FINES i: GRAIN FINES L nu" as 1 9 II I I Fl G. 5

PAIENIEUJULBOISH I 5.826367,

SHEET I4 UF 4 SCALPER INLET FIG. 6 ;RAII \I AND MANIFOLD INE \J I I 2 ELEVATOR 36 4 I OvERFLOW C I EIINER OUTLET MANIFOLD I 60' III I I I II III II I I I I I II I I I IL "L III III I ..-I I 7 GRAIN I I I I I I I I T"III IF I IW j I I I I: II I AM I I'I I" I I II I I .I II III III I VERTICAL 4 L I:I l LL IIL. IiL J CHUTES I i I I I I l FINES I I I I I 22 ACCEPTABLE I I I I 66 GRAIN I I/ I e2 FIG. 7

. ACCEPTABLE 66 GRAIN FINES 1 GRAIN CLEANER BACKGROUND OF THE INVENTION This is a continuation-in-part of my copending US. Pat. application for a Grain Cleaner, filed Jan. 30, 1969, Ser. No. 795,260, now U.S. Pat. No. 3,680,697.

A conventional grain cleaning device includes a chute for feeding a mixture of grain and fines to a shaker box. Within the shaker box in the mixture flow path, a series of spaced openings of equal size provides for gravitational division of the mixture into a plurality of equal streams. The intent is to provide a uniform feed of material to each of a plurality of screening decks disposed in the box. Each of the decks includes a screen with a pan disposed thereunder. The screen is provided with appropriately sized openings to retain the whole grains above the screen and allow the fines to fall onto the pan.

Near the end of each screen and disposed thereon is a baffle. The baffle directs the grain to one side of the screen where it is discharged to a vertically extending chute. A similar baffle on the pan deflects the fines to the other side into a second vertically extending chute.

The first problem existing in the sequence of flow outlined above is the proper division of the flows of material to the screening decks to prevent choking of one screen and starving of another. Unfortunately, the plurality of spaced openings through a plate is inadequate to equally divide the grain-fines mixture. Grain, even though it is substantially dry, will not spread evenly on a flat surface in a short distance; see U.S. Pat. No. 2,908,391 for an example of the prior art. The instant invention has solved the uniform feed problem by providing an inlet or feeding manifold which has a uniform pressure head of grain applied to the various inlets to the screens and adjustable gates in each screen inlet to insure the uniform feeding of each screen. Such uniformity requires a substantially uniform pressure head and adjustable gates; the fact of the need for a uniform pressure head makes substantially unobstructed linear flow through the feed manifold a requirement.

The next problem in the sequence is the screen itself. Often the fines will be very close to the size of the whole grain and will pass partially through the screen openings and remain lodged therein. This is called blinding" of the screen and prior art devices require frequent shutdowns to disassemble the screen and clean it by air blasts or other means.

It has been discovered that where the shaker apparatus has an acceleration of at least three times that of gravity applied thereto and where it provides a vertical throw of the material on the pan which is adequate to strike the underside of the screen, the blinding is almost totally eliminated because the material on the underside of the screen will tend to dislodge the materials blinding the pores. This improvement greatly increases the longevity of operation between the times of shutdown.

The next problem in the line of flow is the baffles disposed within the shaker box. As may be imagined, providing the baffles both above and below the screen tends to reduce its effective area because of the lost space downstream of the baffle. The baffles in the prior art usually extend at an angle of approximately 45and this lost screen space is shown to be an unnecessary waste by this invention. lt was conceived that a separately assembled baffle structure in an outlet manifold on the end of each deck would be a proper solution to this problem. The baffles are placed entirely outside the shaker screen area. Thus, no part of the screen is blocked off from its prime grain separating function. As a result, the total screen is usable for separating grain from fines and the previously discussed solution to the blinding problem would insure throughout the screen rather than only part of the screen. Therefore, an outlet manifold has been provided at the end of the box with two openings for each deck, one for the fines and the other for the whole grain. Baffles are provided therein for deflecting the grain into a plurality of vertically extending chutes and the fines similarly are deflected into an appropriate plane for discharge into other vertically extending chutes.

Another problem which exists in the prior art is the distance of the horizontal grain deflection within the vibrating apparatus. The grain on one side must be pushed half the width of the screen. It is inherent in the physical structure of granular material to resist such movement. As a consequence, some of the power of the vibrator is consumed in this horizontal deflection. That excess consumption of power is largely eliminated by the instant invention. First, the screening decks are inclined at an optimum angle; second, a plurality of vertically extending chutes are provided which reduces the required horizontal deflection; and third, a laterally deflecting structure is provided in each grain chute to cause them to converge into a single duct. The grain exits from the outlet manifold and falls into the vertically extending chutes by gravity. With the gravitationally imparted momentum, the lateral deflections within the chutes require no outside manufactured .power, thus the expense of grain separation is reduced.

BRIEF DESCRlPTlON OF THE INVENTION A chute feeds a mixture of grain and fines to inlet manifolds for a multi-deck screening apparatus. An overflow chute near the top of each manifold maintains a constant pressure head of grain therein. The inlet manifold is attached by suitable structure to a box containing a plurality of screening decks. Substantially dry grain is fed into the inlet hopper which is designed to allow linear flow from its inlet mouth to adjustable gates adjacent the screening apparatus.

A single vibrator is provided for the two shaker boxes with one box above and one box below for structural balance. A plurality of outlets from the feed manifold are provided facing the shaker box screening apparatus and disposed in each outlet is a pivotable gate for regulating the flow of material therethrough, thereby providing a means for insuring uniform flows of the mixture to each of the screening decks.

The multi-deck screens housed in the box are inclined at the optimum angle for conveying grain and adequately separating the mixture. They are agitated by a shaking or vibrating means which is regulated to reciprocate the box with an acceleration of at least three times that of gravity.

Each screening deck includes a pan with a superposed screen. The screen openings are of a size to allow foreign matter, broken grains and undersized grains to pass therethrough and be deposited on the pan. It is intended that whole grains remain above the screen. The vibrating apparatus imparts to the separated material on the pan a vertical throw adequate to have the material strike the underside of the screen and dislodge any materials which may tend to be deposited in the openings of the screen and blind the screening operation.

At the outlet end ofthe box is an outlet manifold which has a plurality of openings at its inlet end to receive the separated material from the screening decks. There are two inlets in the outlet manifold for each deck, one to receive the whole grains from above the screen and one to receive the lines from between the screen and the pan. Provided within the outlet manifold are a plurality of baffles for deflecting the grains and the fines horizontally in opposite directions whereby the grain and fines from each of the screens or pans, re-

spectively, will exit from the outlet manifold into one of a plurality of separate vertically extending chutes. All such material exiting from the outlet manifold will fall into a chute and acquire a momentum due to gravity; to utilize this momentum, a suitable distance below the outlet manifold in each chute is an angularly extending deflector. Grain and fines falling within separate chutes are laterally deflected by these deflectors in opposite directions. Deflected grain from a plurality of chutes will be directed into a single larger chute and thence to a storage bin or the like. Deflected foreign matter will be directed into a separate single chute leading to a refuse pile or other suitable repository.

An object of'this invention is to provide an improved apparatus for separating grain from fines.

Another object is to provide an inlet manifold for regulating uniform flows of material to each of a plurality of screening decks in a vibrating screen grain separator.

Another object is to provide an improvedgrain separator of balanced construction.

Another object is to provide an improved combination of feeding manifold, screening apparatus and outlet manifold in a grain separator.

Another object is to provide an improved structure for channeling streams of separated grain and fines toward storage or disposal areas.

Another object is to provide an improved method of separating grain from fines.

Another object is to provide a multi-deck grain separator inclined at the optimum angle for moving and separating grain and fines.

BRIEF DESCRIPTION OF THE DRAWINGS I FIG. I is a side elevational view of the combination of this invention including a feeding manifold, a vibrating screen housing, a discharge manifold and a plurality of vertically extending chutes;

FIG. 2 is a perspective view of the feeding manifold, partially in section, showing the adjustable outlet openings;

FIG. 3 is a fragmentary elevational view, partially in section, of the box and the decks of separators therein;

FIG. 4 is an exploded view of the elements of the outlet manifold showing the baffles for deflecting the separated grain and fines;

FIG. 5 is a fragmentary plan view of the screening area and the outlet manifold, partially in section;

FIG. 6 is a diagrammatic view of the flow path of the grain and fines; and

FIG. 7 is an elevational view of the vertically extending chutes.

PREFERRED EMBODIMENT This invention is related to a multi-deck grain cleaner or separator in general, and in particular to separators for corn and soybeans. It includes a chute 10 for feeding mixtures of grain and fines to feeding manifolds or hoppers l2 and 13 which in turn feed a vibrating apparatus l5. Substantially identical upper and lower shaker boxes or housings l4 and 16, respectively, are secured together in spaced relationship by rigid side members 17. Disposed between the boxes is a vibrator 18 for shaking or reciprocating the structure. The particular machine for vibrating is not a novel part of this invention and any conventional vibrating mechanism may be employed. At the outlet end of each of the shaker boxes is an outlet manifold 20 which guides the separated material to a plurality of outlet chutes indicated generally at 22. v

As the boxes are substantially identical, only one will be described. The mixture of grain and fines is dropped into the feeding manifold 12 through an inlet opening 24 at the top thereof. The bottom wall 26 of the inlet manifold 12 is disposed adjacent the bottom edge of the shaker box 14.

At the side of the inlet manifold 12, juxtaposed to the housing 14, are a plurality of outlets 28. One outlet 28 is provided and aligned to feed each of a plurality of screening decks 27 secured in the housing 14. The outlets 28 are disposed just above the screen 29 of each of the screening decks 27 and to insure a uniform feed of grain and foreign matter to each of said screening decks, gates 30 are provided within each outlet. These gates 30 may be individually adjusted to prevent the choking of one screening deck and the starving of another or they may be locked together for group adjustment, as desired. Each gate 30 is pivoted at 32 about an axis at one side edge extending perpendicular to the direction of grain flow.

Obviously the grain must be substantially dry to minimize agglomeration and clogging at the gates 30. Additionally, to maintain a substantially uniform pressure head on all the gates, there can be no intermediate obstructions along a linear path from opening 24 to gates 30.

As best seen in FIG. 2, the edge of each gate 30, remote from the pivot axis, is tapered to a sharp edge 33. The sharp edge facilitates the flow of grain past the gates and provides a definite dividing line between flow paths. Also, when separating com, the sharp edge will sever any corn husks which may be in the stream, thereby preventing clogging.

In order to properly adjust the gates for continual uniform feed, there'must be a constant pressure head of grain applied to the gates. As a result of this fact and in addition to the unobstructed flow within the hopper 12, an internal rear wall 34 is provided within the inlet manifold 12. Just above the internal rear wall 34 is an overflow opening 36 which feeds an overflow chute 38. The continual grain separation process includes feeding the grain-fines mixture through the inlet opening 24 at a faster rate than the rate of exit from the outlets 28. Thus, at all times there may be some material overflowing the inlet manifold 12 through the overflow opening 36 and into the overflow chute 38 where it will be returned to the feed chute 10 or to storage bins (not shown).

It should be noted that the irregularity of the individual grains and their natural friction provides a back force within the inclined branches of the feed chute whereby the effective grain pressure head in each inlet manifold may be measured from point 39, see FIG. 1. Point 39 is the location in each branch where the grain has substantially a straight line drop into'the inlet manifolds 12 and 13.

Resilient mountings 40 at each corner of the shaker boxes serve to support the separator above a substrate 41. Such mountings have been found convenient for preventing the transfer of vibrations from the separator to the supporting structure.

Each of the decks 27 includes a screen 29 fixed in position above a pan 46. Appropriate sealing devices 47 are provided along the edges of the screen and the pan to prevent intermingling of the separated materials. The screen, per se, may be woven wire, a perforated sheet metal piece or some woven cloth, depending upon the particular kind of separation desired. The work screen" is intended to include any type of apparatus such as this, which is involved in a separating operation.

As is conventional, the screening decks 27 are encompassed in

shaker boxes

14 and 16 and are caused to vibrate by the vibrator 18. This agitates the grain and fines on the screen 29 and the fines tend to pass through the screen openings and be deposited on the pan 46. Moreover, in this invention, the vibrator 18 is regulated to impart an acceleration to the

boxes

14 and 16 of at least three times that of gravity and the pan 46 and screen 29 are so spaced and regulated with the vibrator 18 that a vertical throw is imparted to the fines which is adequate to cause them to strike the underside of the screen 29 and dislodge any materials in the openings which might tend to blind the screen. The spacing of the screen 29 and the pan 46, the rotational velocity of the vibrator 18, etc. may be experimentally determined for any particular sizes of grain, as necessary. In the preferred embodiment the pan-screen spacing is about one inch and the vibrator rotates at about l,l l3 rpm. In addition, the optimum angle of inclination, in the range l5-20, for the screening decks 27 should be determined. With many of the ordinary grains, the deck should incline at about 17. When the grain and fines arrive at the outlet end of the screening deck 27, it is anticipated that substantially all of the fines will have been separated from the whole grains where the optimum angle is used.

Each deck has two outlets to the outlet manifold 20. An upper outlet 48 is disposed immediately above the screen 29 for the grain. A lower outlet 50 is provided between the screen 29 and the pan 46 for receiving the separated fines.

Two passages are provided in the outlet manifold for each deck, one is a grain passage 52 and the other is a fines passage 54. Disposed in each passage are a plurality of baffles 56 which deflect the grain and fines horizontally in different directions. The outlet passages and baffles are uniformly disposed from deck to deck, whereby the deflections tend to direct the grain toward a passage of smaller cross-sectional area downstream and eventually to a plurality of vertically extending chutes 58 for receiving the separated cleaned grain and a plurality of different chutes 60 for receiving the fines which have been separated from the grain. Thus, the

elements making up vertically alternate passages are in register.

In each of the

chutes

58 and 60, below the outlet manifold 20, is an angularly inclined deflector 62. The deflectors in the grain chutes are inclined in one direction with the deflectors in the fines chutes inclined in another direction. This structure allows all the grain chutes 58 to empty into a larger single chute 64. Similarly, a single chute 66 accommodates the discharge of all of the tines chutes 60. The enlarged single grain chute 64 may extend to storage bins or elsewhere, as desired.

In operation, the vibrator 18 is actuated giving the two

boxes

14 and 16 an acceleration of at least three times that of gravity. A mixture of fines and grain is continuously fed to the

manifolds

12 and 13 through the chute 10. As the mixture flows into the manifolds, the outlets 28 therefrom are adjusted to feed uniform streams of the mixture of each of a plurality of superposed screening decks 27. As the screening decks 27 are rigidly fixed within the boxes, they also receive an acceleration of approximately three times that of gravity. The grain and foreign matter on the decks are agitated by the vibrating of the screens and the fines, including the foreign matter, broken grains and undersized grains will fall through the screen openings onto a pan 46 located beneath the screen. Grain is retained above the screen 29 because the openings are specifically structured smaller than a normal sized grain of the particular type being separated.

As the grain passes along the screen toward the outlet of the box, certain of the grains which are very close in size to the openings through the screen may be lodged or trapped. To overcome this, correlation between the vertical throw of the vibrating apparatus and the acceleration is regulated to toss the fines on the pan 46 upward to strike anything which may be blinding any of the openings and adequate momentum is imparted to the fines to dislodge anything which may be tending to blind the scrren. Passing on through the box, the separated grains exit into a passage in an outlet manifold which is immediately above a similar passage which receives the separated fines.

The exits from the box take the separated materials into an outlet manifold which is made up of a plurality of superposed passages for receiving the grain and fines. Within each passageway through the outlet manifold are a plurality of baffles for deflecting material in a horizontal direction. The grain will be deflected to one side, the fines to the other side and the grain and fines will exit from the outlet manifold into one of a plurality of vertically extending chutes. The fines will exit into certain chutes and the grain will exit into certain other chutes.

Gravity will carry the material in the chutes downward to deflecting apparatus within each chute. The grain will be deflected laterally to one side and the fines laterally to the other side. Each of the grain chutes merges into a larger single grain chute for receiving all of the grain and a similar chute receives all of the discharge from the fines chutes. The grain in its single chute and the fines in its single chute may be conducted to appropriate disposal or storage apparatus as desired.

For ease of description, the principles of the invention have been set forth in connection with but a single illustrated embodiment. It is not intended that the illustrated embodiment nor the terminology employed in describing it be limiting inasmuch as variations in this embodiment may be made by those of ordinary skill in the art without departing from the spirit of the invention. Rather it is desired that the invention be restricted only by the scope of the appended claims.

I claim:

l. A feeding manifold for discharging a flow of substantially dry granular material through each of a plurality of openings, said manifold comprising:

a chute-like structure having continuous side wall with an uppermost end and a lowermost end; an inlet adjacent said uppermost end adapted to receive said granular material and a plurality of outlets disposed adjacent said lowermost end, said chute-like structure being disposed so that said granular material will flow linearly from said inlet toward said outlets by gravity;

an adjustable gate disposed at each outlet and movable between fully opened and fully closed conditions for selectively regulating the flow of said material outwardly of said outlets; and,

a material overflow outlet disposed adjacent said uppermost end of said chute-like structure for maintaining a constant pressure head of said granular material.

2. The feeding manifold of claim 1 wherein each gate is individually adjustable.

3. The feeding manifold of claim 1 wherein the gates are pivotable for adjustment about an axis near one edge thereof.

4. An apparatus for separating dry granular material substantially comprised of whole kernels of grain and fines including in combination:

an enclosed feeding manifold having uppermost and lowermost ends with a material inlet disposed adjacent said uppermost end and a plurality of material outlets disposed adjacent said lowermost end, said inlet adapted to receive said material with said manifold being dimensioned to allow unobstructed linear flow of said material from said inlet toward said plurality of outlets; an overflow outlet disposed adjacent said uppermost end for maintaining a constant pressure head of said material; and, adjustable gates disposed at each of said outlets for selectively regulating streams of said material flowing outwardly therefrom;

a multi-deck separator adapted to receive said streams as they issue from said outlets, said separator including a screening deck in operative association with each material outlet; and,

means for vibrating said manifold and said separator.

5. The feeding manifold of claim 4 wherein each gate is individually adjustable.

6. The apparatus of claim 4 wherein the screening decks are inclined at an angle in the range of l520 to facilitate flow of said streams and to insure adequate separation of said grain from said fines.

7. The apparatus of claim 6 wherein the angle is approximately 17.

8. The feeding manifold of claim 7 wherein each gate is individually adjustable.

9. The feeding manifold of claim 6 wherein each gate is individually adjustable.

Claims

1. A feeding manifold for discharging a flow of substantially dry granular material through each of a plurality of openings, said manifold comprising: a chute-like structure having continuous side walls with an uppermost end and a lowermost end; an inlet adjacent said uppermost end adapted to receive said granular material and a plurality of outlets disposed adjacent said lowermost end, said chute-like structure being disposed so that said granular material will flow linearly from said inlet toward said outlets by gravity; an adjustable gate disposed at each outlet and movable between fully opened and fully closed condiTions for selectively regulating the flow of said material outwardly of said outlets; and, a material overflow outlet disposed adjacent said uppermost end of said chute-like structure for maintaining a constant pressure head of said granular material.

4. An apparatus for separating dry granular material substantially comprised of whole kernels of grain and fines including in combination: an enclosed feeding manifold having uppermost and lowermost ends with a material inlet disposed adjacent said uppermost end and a plurality of material outlets disposed adjacent said lowermost end, said inlet adapted to receive said material with said manifold being dimensioned to allow unobstructed linear flow of said material from said inlet toward said plurality of outlets; an overflow outlet disposed adjacent said uppermost end for maintaining a constant pressure head of said material; and, adjustable gates disposed at each of said outlets for selectively regulating streams of said material flowing outwardly therefrom; a multi-deck separator adapted to receive said streams as they issue from said outlets, said separator including a screening deck in operative association with each material outlet; and, means for vibrating said manifold and said separator.

6. The apparatus of claim 4 wherein the screening decks are inclined at an angle in the range of 15*-20* to facilitate flow of said streams and to insure adequate separation of said grain from said fines.

7. The apparatus of claim 6 wherein the angle is approximately 17*.